Comment by mlyle
2 days ago
Reducing carbon emissions means electrifying a lot of things that were not electric before. We are going to need a lot more base generation than we have now.
Large grids, overbuilding renewables, diversity of renewables, short and medium term storage, and load shedding/dynamic pricing are all good starts but IMO won’t be enough— we should scale up nuclear too.
More, but not as much more as people often naively expect because it turns out converting liquid fuel into motion by burning/ exploding the fuel isn't very efficient on a small scale whereas electric motors are very efficient, so 1TW year of "People driving to work" in ICE cars does not translate into needing 1TW year extra electricity generation if they have electric cars instead, let alone 1TW year of extra network capacity to deliver it.
Where we're replacing fossil fuel heat with a heat pump we don't get that efficiency improvement from motors - burning fuel was 100% efficient per se, but the heat pump is > 100% efficient in those terms because it's not making heat just moving it.
Nuclear is much less popular than almost any generation technology, so you're fighting a significant political battle to make that happen.
We need a lot more. Right now only about 25 to 33 pc of our energy consumption is electric. Some of the rest will get significant efficiency benefit like you mention — cars, building heating, etc. Others, much less so— high temperature industrial heat, long distance transport, etc.
Reaching current nighttime use with storage and wind and existing hydro looks infeasible, and we need a minimum of twice as much.
Power to gas (and back to power or to mix with natural gas for existing uses) is probably a part of this, but nuclear improves this (allowing there to be less of it and allowing the electrolysis cells to be used for a greater fraction of the day.
People have run the numbers. We need about 30% more. Which is a lot, but it's spread over 20-30 years, so it's not a lot each year.
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Building heating won’t see much increase in efficiency from going electric compared to a high efficiency gas furnace.
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One of the bigger other sources of emissions is transport; transport requires some of the electricity is condensed into a portable form regardless of the specifics — batteries, hydrogen, chunks of purified metal to burn, whatever — and that condensation means it doesn't get any extra novel benefit from expensive-but-consistent nuclear over cheap-but-predictably-intermittent renewables.
The scale is such that if we imagine a future with fully electrified cars, the batteries in those cars are more than enough to load-balance the current uses of the grid, and still are enough for the current uses of the grid when those batteries have been removed from the vehicles due to capacity wear making them no longer useful in a vehicle.
The best time for more nuclear power was the 90s, the second best was 10 years ago; unless you have a cunning plan you've already shown to an investor about how to roll out reactors much much faster, I wouldn't hold your breath on them.
> and that condensation means it doesn't get any extra novel benefit from expensive-but-consistent nuclear over cheap-but-predictably-intermittent renewables
This assumes you can do just the condensation during the day— E.g. you are amortizing the electrolyzers capital cost over just times when there is surplus power instead of something closer to 24/7.
Batteries to have solar 24/7 will be dirt cheap soon. The question is: is it cheaper to build nuclear and run the electrolyzers at the same rate the whole year or use solar and run them much less during the winter. Where much less is a function of latitude
>we should scale up nuclear too.
With a 5x higher LCOE and lead times of 15-20 years instead of 1-2 for solar/wind deployments, allocating money to scale up nuclear as well will just make the transition happen slower and at higher cost.
I don’t think we can scale up storage enough at any reasonable cost.
We need about 30TWh of batteries to decarbonize the world's grid. China has 1TWh per year of capacity, increasing 50% per year.
Cost is currently $35/kWh, dropping 20% per year.
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We can start worrying about storage once we reach 60-80% renewable and just keep using fossil fuels as backup. Nuclear doesn't replace storage (at least not if you don't want to run your nuclear plants at like half capacity)
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